1. Field of the Invention
The present invention relates to a method and apparatus for processing coded information received through a phone line during the non-active intervals of a ringing period. More particularly the present invention relates to a method and apparatus allowing a called phone subscriber, when present at the location where the apparatus of the present invention is provided, to know that the calling party is one who has knowledge of one of the pre-established codes when his phone set receives a call followed by the reception of the pre-established code and before the called party answers the call. The present invention relates also to a method and apparatus for performing at the receiving end any electrically controllable operation by the use of a pre-established code.
2. Description of the Prior Art
A phone subscriber is commonly pestered by innumerable unwanted phone calls, even during the small hours or when he is busy and he does not desire to be perturbed. Until now, no effective method is known to obviate such inconveniences. The most simple method used is to have a private exchange attended by an operator who acts like a screen between the calling party and the called party. However it may happen that the oeprator is not sure of the importance of the call; in such case the operator must assume the responsibility of transferring the communication, in which case said operator must interrupt the called party or, in the opposite case, look for an excuse for obviating said interruption. In this latter case it may happen that the operator was wrong in evaluating the importance and/or the urgency of the message motivating the call. A device, supposedly intended for obviating inconveniences of this sort, is the automatic answering recorder. However, this kind of apparatus does not allow to know if the calling party is a desired one. Such an apparatus is more useful for knowing which persons have called during a period of absence of the phone subscriber. Later on he may replay all the recorded messages which have been left by the calling parties during his absence. It is not practical to put in operation such an apparatus when the phone subscriber is present, because he can lose the opportunity of answering important or simply desired calls at the moment when they are being received. It is also possible to resort to a company rendering answering services. While such services obviously offer several advantages, they have also various inherent drawbacks. One of them is that the answering service retains the phone line of the phone subscriber during all the time the service is rendered. Another drawback is that the operators of such services become acquainted with the nature of the received messages; thus no privacy or secrecy may be maintained. Still another drawback is that there is a considerable delay between the reception of the message by the answering service and the moment at which the called subscriber becomes acquainted therewith. Another device used by some phone subscribers to get privacy, and which is available on the market, is a simple switch connected in series with the circuit of the ringing bell of the phone set. When the switch is open, the bell will not sound and thus the phone subscriber will never become aware of the fact that a phone call is being made to him. This is obviously a very inconvenient method, since the phone subscriber may miss one or more important and/or urgent calls. The phone subscriber has no means to know that a call is being made and if the calling party may or not be a desired one. Another very important drawback is that, if the phone subscriber forgets to close the switch once he desires to be again in conditions of receiving calls, he may remain uncommunicated during several hours, or even days, without being aware of the fact.
Before starting the description of the present invention and for a better understanding thereof, it is considered convenient to give a statement of the scope within which several of the terms and expressions, used both in this specification and in the accompanying claims, must be framed.
"Phone line".
The entire circuit established from the output of the calling phone apparatus, through the exchange or exchanges intervening in the call up to the input of the apparatus of the present invention, or also any of the partial portions of such circuit, such as from the calling apparatus up to the exchange corresponding thereto, from this exchange to another exchange when the calling and the called apparatus pertain to different exchanges, or from the exchange to which the called apparatus pertains up to the input of the called apparatus proper.
"Character".
Each of the discrete components of a coded information which has been sent through the phone line and circulating through the circuits of the apparatus of the present invention, but different from the conventional information which represents the distinctive characteristic of a conventional subscriber apparatus. Said conventional information may include numerical characteristics of the called apparatus, its exchange, area, country (in the case of international calls), etc. The characters of the information which is not the conventional one, may be one tone or a pair of tones (or frequencies) as those of a "Touch-Tone" system.
"Code".
Group of characters constituting an information different from the conventional information mentioned above and serving only for specific uses in the present invention. A code may comprise a single character or a plurality thereof.
"Calling end".
The end of a phone line from which a call is originated.
"Called end".
The end of a phone line to which the communication requirement is directed.
"Calling party".
A person, or an electric or electronic device, which originates the communication requirement by means of an apparatus at the calling end.
"Called party".
A person, or an electric or electronic device, which receives from the exchange the communication requirement originated by the calling party.
"Conversation loop".
The loop which is closed between the calling end and the called end (through one or more intervening exchanges) once the call has been attended, indistinctly by a person unhooking the phone receiver, or by an electric or electronic device automatically connecting on the called end of the phone line an electric impedance equivalent to that offered by an unhooked conventional phone set.
"Ringing loop".
An alternating current loop established between the called phone set and its exchange so as to be able to send from the exchange to the called phone set alternating current wave trains serving for energizing the bell of the called phone set, but before this latter is attended personally or automatically. At the same time a ringing loop is also closed between the calling phone set and its exchange, so as to allow the calling party to know that the called phone set is being ringed. Once the call has been attended, the ringing loop is opened and the conversation loop is established.
"Utilization circuit".
Any circuit which is connectable to two or more of the outputs of the present invention apparatus for automatically actuating one or more devices which are electrically controllable, for example an air conditioning apparatus, one or more electric lights, an alarm, the automatic coupling of the called phone line to another different phone line, etc., always in response to the reception and validation, by the present invention aapparatus, of a code corresponding exclusively to said utilization circuit.
"To activate an utilization circuit".
In addition to its obvious meaning, related to the expression defined immediately above, it is also used herein as an equivalent of "to inactivate an utilization circuit". This may be easily understood by bearing in mind that for inactivating an electronically controllable device it is necessary to activate, through one of the outputs of the present invention apparatus, an intermediary device which in its turn will inactivate the device which is desired to control.
"Ring-back signal".
In the case of the apparatus of the present invention, it refers to a signal that is automatically sent, from the called end and by means of the present invention apparatus, to the calling phone set to advise the calling party that at the called end one of the operations that may have been ordered by the present invention apparatus has been carried out, such as the validation of a code, the fact that the called phone set has been attended, that an utilization circuit has been activated or inactivated, etc. Commonly the term "ring-back" refers to the ringing of the bell of a phone set; however in the case of the present invention it may be also an audible tone or any other acoustic, visual or other information allowing the calling party to know that such operation has been performed at the called end.
"Connected".
Indicates a direct electrical connection between two points.
"Coupled".
Indicates indistinctly a direct electrical connection or an indirect electrical connection between two points; the indirect connection may be established through one or more passive or active components such as resistors, capacitors, inductors, transistors, triacs, switches, etc., single or in combination.
"Active intervals of the ringing period".
The intervals of the ringing period during which the exchange is sending the ringing signal proper.
"Non-active intervals of the ringing period".
The intervals of the ringing period during which the exchange is not sending ringing signal; that is to say, the time comprised between two consecutive active ringing intervals. These non-active intervals are commonly called interringing intervals.
"Ringing period".
The entire period of time during which the ringing loop remains closed. In other words it is the sum of all the active plus the non-active intervals.
"To dial".
It must be interpreted in the sense of performing the operation of actuating the keys of a keyboard of the "Touch-Tone" telephonic system.
"Access code".
A code sent through the phone line by the calling party during non-active intervals of a ringing period and in response to which the apparatus of the present invention will close the conversation loop, thereafter allowing the sending of a second code intended to perform other subsequent operations.